xxix 



bed, but his intellect remained unclouded. He regarded his approaching 

 end with composure, and died on the 4th of April, 1870. He was buried 

 on the 8th in the Dorotheenstadt Cemetery. 



The researches of Magnus, on a large number of widely different sub- 

 jects, extend over a space of not less than forty-five years. Almost all of 

 them appeared in Poggendorff's ' Annalen,' and the most part also in 

 the publications of the Berlin Academy of Sciences. His first memoir, 

 published in 1S25, while yet a student, was on the reduction of the 

 oxides of cobalt, nickel, and iron by hydrogen, and on the spontaneous 

 inflammability of these metals in a state of fine division. In 1827 he 

 published researches on the solubility of sulphur and selenium, without 

 oxidation, in sulphuric acid. Between 1827 and 1833 he investigated 

 the combination of platinous chloride with the elements of ammonia, 

 the composition of sikrosmine, brochautite, vesuvian, the diminution of 

 density of vesuvian after fusion, and discovered sulphovinic, sethionic, and 

 iseethionic acids and their salts, and, conjointly with Amermiiller, periodic 

 acid. He experimented on the gases contained in blood, the exhaustion 

 of soils, and on the nutrition of plants. He also invented a maximum 

 thermometer, and employed it to find the temperature of an artesian well 

 at Riidersdorf, and afterwards, in an improved form, to find the tempera- 

 ture of a similar well at Pitzpuhl. He undertook researches on the boiling 

 of mixed fluids, and the temperature of the vapour of saline solutions. 

 Between 1841 and 1844 he carried out a most important series of experi- 

 ments on the expansion of atmospheric air, hydrogen, and other gases, 

 and ou the pressure of the vapour of water at temperatures between 6° C. 

 and 104 c C. TTithout being aware that Magnus was engaged in these 

 researches, Regnault was occupied with the same investigation ; and the 

 results obtained by these ttvo experimenters were published almost simul- 

 taneously. Their close agreement affords a striking proof of the care with 

 which they observed and the excellence of their methods, and affords a gua- 

 rantee of the accuracy of the determination of the expansion of air and the 

 pressure of the vapour of water, data of the utmost importance in physical and 

 chemical investigations. He made observations on electromagnetic pheno- 

 mena and thermoelectric currents, on the forms of streams of spouting 

 fluids, the deviation of rifled balls from a vertical plane, the condensa- 

 tion of gases on the surfaces of solids. His later researches were mainly 

 on the transmission of heat through gases and vapours, the differences 

 of the nature of the heat radiated from smooth and rough surfaces, and 

 the polarization of heat. His last communication to the Academy of 



Sciences was made on the 11th of October, 1869. 



He was Corresponding Member of the French Institute, and actual or 



Corresponding Member of many other Academies and learned Societies. 

 The preceding outline of the life and labours of Magnus is extracted 



from a Biography by Professor Hofmaun read before the Chemical Society 



of Berlin. 



